I run a minimum water temp of 205, and a maximum of IDK, 207. Yeah the gauge works.
The mechanical fan, on a clutch, mostly only works at low vehicle speeds, so who cares how much power it sucks, you are at part throttle! You're first priority should be to ensure your engine doesn't self-destruct, not to worry about a couple of,or few, horsepower. Oh but on HotRod tv..... yadayada, who puts on a direct drive fan and spins it to 6500, with the vehicle at rest? Who?
Here's a realworld test. Install your 7 blade fan and thermostatically controlled clutch. Now run the engine up to 1300 with the fast idle cam, and watch your tach while waiting for the clutch to cycle on. And wait and wait; listen here it comes, quick watch the tach. What?! The engine didn't stall? How can that be, the fan sucks mega power.Everybody knows that. What 1300 isn't fast enough? What's your rpm in drive at 30mph? How much power does it take to maintain 30 mph? How many people, back in the carburated hey-day, ever complained about their engine stalling when the fan cycled on?
Here's the thing, it takes a clutched mechanical fan a few seconds to cool your engine down from say 210 to 200. It takes your electric fan how long to do the same job? a minute and a half, hey that's pretty good. So if it draws 20 amps and is 10% efficient, that would be 3.6hp. Say what? You got two of them? Well that would be 7.2hp then. So how does 7.2hp for a minute and a half, compare to 30 seconds and 7.2hp for the mechanical. IDK either, but I think the mechanical fan is winning, by a ratio of 1 to 3,lol.
Disclaimer; obviously I am pro,mechanical-fan, and after 45 years or more of trouble-free motoring, that stands to reason. And so I biased the conversation and the tests in my favor. If your car burns the tires thru first and maybe second gear, why would you care how; wait am I in the racers forum? No? ok- then; why would you care about 5 or 7 or even 30 horsepower going to a mechanical fan? No1 you have a preponderance of power anyway; no2 the fan only runs for a few seconds atta time; and no3 after 30/35 mph the fan may not be moving any air at all! cuz the car-in-motion is now ramming air thru the rad and the fan is freewheeling.
And finally
How do you tune a carburated engine, sucking underhood air, in which the temp is varying 30,40,50, or more degrees?
IDK either.
Oh yeah, one more thing; with a thermostically clutched fan, you don't need a 3-row rad, nor a honking big one, or one made of exotic materials. Heck it doesn't even need to be new. I just slapped what I had, in there in 1999,and she's still going strong despite being a 45 year old 318 A/C rad.
I tell you one thing, I'd never willingly install an electric fan on my engine(s).
Your results may vary.
Yeah I know I sound like a dick, sorry,lol.